Inside the driver: the H bridge
Four switches around a motor make it go both ways. An L293D on a breadboard: the truth table, braking against coasting, back EMF, and why half the PWM is not half the speed.
Open it in the simulatorAll paths
Motors and motion
DC motors on a driver, the H bridge inside it, servos, a stepper on an A4988, an encoder that measures what the motor did, and a 2WD robot car with ultrasonic eyes and line sensors.
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What you will build
3 projects, built step by step
7 lessons in 4 chapters, about 4 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator.
A stepper on an A4988: STEP and DIR
A NEMA 17 moves in exact steps with no sensor at all. Two wires from the Uno, microstepping from three pins, the current limit you set with a screwdriver, and how a stepper misses steps.
Open it in the simulatorBoss: a robot car with eyes and line sensors
The finished robot: a 2WD car on a MOSFET DRV8833 with an ultrasonic eye and two TCRT5000 line sensors, run by a four-state machine that hunts, charges and never drives off the edge.
Open it in the simulatorThe map
Chapter by chapter
Each lesson opens when the one before it is done, and each chapter ends in a project.
Chapter 1
DC motors
Speed with PWM, direction with an H bridge, and where the volts go.
- Open187 XP
A DC motor on a driver: speed and direction
Two gear motors on an L298N: why a pin cannot run a motor, two inputs for direction, PWM on the enable for speed, and the volts a bipolar driver keeps for itself.
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- ProjectLocked374 XP
Inside the driver: the H bridge
Four switches around a motor make it go both ways. An L293D on a breadboard: the truth table, braking against coasting, back EMF, and why half the PWM is not half the speed.
0 of 5 steps
Chapter 2
Servos and steppers
Motors that go to an angle, and motors that count their steps.
- Locked169 XP
A servo: an angle, not a speed
A hobby servo is a motor, a gearbox, a potentiometer and a control loop in one box. Drive it with a pulse width, follow a slider, and learn why it needs its own power.
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- ProjectLocked338 XP
A stepper on an A4988: STEP and DIR
A NEMA 17 moves in exact steps with no sensor at all. Two wires from the Uno, microstepping from three pins, the current limit you set with a screwdriver, and how a stepper misses steps.
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Chapter 3
Feedback
An encoder measures what the motor really did, and the code corrects.
- Locked187 XP
An encoder: measure what the motor really did
A gear motor with a Hall encoder on an L9110S pumps an exact dose: count pulses on an interrupt, work out speed from them, and slow down before the mark so it stops on it.
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Chapter 4
Boss project
A 2WD robot car that avoids walls, hunts with its eye and never crosses the line.
- Locked187 XP
Boss part 1: a car that avoids walls
A 2WD chassis on an L298N with an HC-SR04 on the front: time an ultrasonic echo, turn it into millimeters, and write the look-then-decide loop every robot starts from.
0 of 5 steps
- ProjectLocked400 XP
Boss: a robot car with eyes and line sensors
The finished robot: a 2WD car on a MOSFET DRV8833 with an ultrasonic eye and two TCRT5000 line sensors, run by a four-state machine that hunts, charges and never drives off the edge.
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Syllabus
Every lesson in the course
All 7 lessons, in order, each with what it covers. Any of them opens in the editor right away.
DC motors
- A DC motor on a driver: speed and directionTwo gear motors on an L298N: why a pin cannot run a motor, two inputs for direction, PWM on the enable for speed, and the volts a bipolar driver keeps for itself.
- Inside the driver: the H bridgeFour switches around a motor make it go both ways. An L293D on a breadboard: the truth table, braking against coasting, back EMF, and why half the PWM is not half the speed.
Servos and steppers
- A servo: an angle, not a speedA hobby servo is a motor, a gearbox, a potentiometer and a control loop in one box. Drive it with a pulse width, follow a slider, and learn why it needs its own power.
- A stepper on an A4988: STEP and DIRA NEMA 17 moves in exact steps with no sensor at all. Two wires from the Uno, microstepping from three pins, the current limit you set with a screwdriver, and how a stepper misses steps.
Feedback
- An encoder: measure what the motor really didA gear motor with a Hall encoder on an L9110S pumps an exact dose: count pulses on an interrupt, work out speed from them, and slow down before the mark so it stops on it.
Boss project
- Boss part 1: a car that avoids wallsA 2WD chassis on an L298N with an HC-SR04 on the front: time an ultrasonic echo, turn it into millimeters, and write the look-then-decide loop every robot starts from.
- Boss: a robot car with eyes and line sensorsThe finished robot: a 2WD car on a MOSFET DRV8833 with an ultrasonic eye and two TCRT5000 line sensors, run by a four-state machine that hunts, charges and never drives off the edge.
Keep going
The next course on your track
Motors and motion is part of the embedded track, a ladder of courses from zero to expert.
Embedded on the ESP32-C3
A 32 bit RISC-V board at 160 MHz. Its own peripherals, its own 3.3 V rules, and a console at the end of it.
Open the next courseEmbedded track
Arduino, ESP32, Raspberry Pi Pico and STM32: pins, timing, buses, motors, WiFi, registers and debugging, every lesson checked on a simulated board.
See every course on the trackKits
Build it on your bench too
Every lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts.
Robot Car Kit
An Uno, a 2WD chassis, two motor drivers, an ultrasonic eye and two line sensors.
Open the kitFind your kit
Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins.
See every kitQuestions
About Motors and motion
Is Motors and motion free?
Yes. All 7 lessons of Motors and motion are free and run in your browser, with nothing to install and no parts to buy before you start.
Do I need a real Arduino Uno R3?
No. Every lesson runs on a simulated Arduino Uno R3 with its parts on the canvas, and the simulator checks each step as you go. When you want to build it for real, the same wiring and code work on a real board.
How long does Motors and motion take?
About 4 hours: 7 lessons in 4 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off.
What will I build?
Each chapter ends in a project that puts it together: Inside the driver: the H bridge, A stepper on an A4988: STEP and DIR and Boss: a robot car with eyes and line sensors.
Where do I start?
With "A DC motor on a driver: speed and direction", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.